EXPERIMENTAL CELL RESEARCH
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2017
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IF 3.546
Yong Yang,Zhiyu Xi,Yuan Xue,Jie Ren,Yuhao Sun,Baofeng Wang,Zhihong Zhong,Guo-yuan Yang,Qingfang Sun,Liuguan Bian
Oxidative stress mediated secondary injury contributes to neurological deterioration after intracerebral hemorrhage (ICH). Astrocytes, the most dominant cells in the central nervous system (CNS), play key roles in maintaining redox homeostasis by providing oxidative stress defense. Hemoglobin (Hb), the primary component released by hemolysis, is an effective activator of astrocytes. Hemin, the product of Hb degradation, is highly toxic due to the induction of reactive oxygen species (ROS). We speculate that Hb-activated astrocytes are resistant to hemin-induced toxicity. To verify our speculation, Hb-pretreated astrocytes were exposed to hemin, intracellular ROS accumulation and cell apoptosis were evaluated. Heme oxygenase 1 (HO-1) and nuclear transcription factor-erythroid 2 related factor (Nrf2) expression were observed to explore the potential mechanism. The results demonstrated that Hb induced upregulation and nuclear translocation of Nrf2 in astrocytes, resulted in HO-1 upregulation, which contributed to reduced ROS accumulation and apoptosis rate . Knocking down Nrf2 expression by siRNA suppressed Hb-induced upregulation of HO-1 expression and increased the susceptibility of Hb-pretreated astrocytes to hemin-induced toxicity. Taken together, Hb-activated astrocytes acquired resistance to hemin-induced toxicity via Nrf2/HO-1 pathway. This phenomenon can be considered as the adaptive self-defense in the pathological process of ICH. Hb pre-warned astrocytes and enhanced their capability of handling the coming hemin “flood”. Nrf2/HO-1 may be employed as a target for neuroprotection after ICH.
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Microorganisms
·
2024
·Vol. 12
·期 7
·1381
·
IF 4.1
Xuezhi Shao,Hongliang Fang,Tao Li,Liyan Yang,Dengfeng Yang,Lixia Pan
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze the oxidative cleavage of recalcitrant polysaccharides. There are limited reports on LPMOs capable of concurrently catalyzing the oxidative cleavage of both cellulose and chitin. In this study, we identified and cloned a novel LPMO from the newly isolated bacteriumChitinilyticum aquatileCSC-1, designated asCaLPMO10. When using 2, 6-dimethylphenol (2, 6-DMP) as the substrate,CaLPMO10 exhibited optimal activity at 50 °C and pH 8, demonstrating good temperature stability at 30 °C. Even after a 6 h incubation at pH 8 and 30 °C,CaLPMO10 retained approximately 83.03 ± 1.25% residual enzyme activity. Most metal ions were found to enhance the enzyme activity ofCaLPMO10, with ascorbic acid identified as the optimal reducing agent. Mass spectrometry analysis indicated thatCaLPMO10 displayed oxidative activity towards both chitin and cellulose, identifying it as a C1/C4-oxidized LPMO.CaLPMO10 shows promise as a key enzyme for the efficient utilization of biomass resources in future applications.
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Molecular Catalysis
·
2024
·
IF 3.9
Yan-Fei Liang,Shuai Feng,Dan Wu,Meng Ma,Jin-Tao Ren,Qian Zhao,Wen-Yun Gao,Heng Li
1-Deoxy- D- xylulose-5-phosphate synthase (DXS) is the first rate-limiting enzyme in the 2-methyl- D- erythritol-4-phosphate (MEP) terpenoid biosynthetic pathway. To explore the active sites of the protein, we made a series of mutations to the key amino acid residues of Escherichia coli DXS including H49, R420, D427, and R478. The results show that several mutants including H49Q lose almost all their catalytic activity in DXP synthesis, but the double-point mutants H49QD427H and H49QD427 N recover 100 % activity of the wild type enzyme. The kinetic characterization displays that the affinity of the double-point mutants for pyruvate and D- glyceraldehyde-3-phosphate only slightly decreases. We also assessed impact of the mutation on the oxidative decarboxylation activity of all the mutants. Despite the fact that H49QD427H and H49QD427 N get back the full activity with regard to DXP synthesis, their oxidase activity remains unrestored. Furthermore, we assayed the acceptor substrate spectrum of the mutants and the results show that a large portion of them catalyzes ligation between pyruvate and nitrosobenzene to form N-phenyl-N-hydroxyacetamide, whereas R420D, R420F, and D427H exhibit activity in connection of pyruvate and benzaldehyde to afford phenylacetocarbinol (PAC), with the first two mutants yielding ( S )-PAC (yields 21 %-25 %, ee values 71–75 %) while D427H furnishing ( R )-PAC (yield 41 %, ee value 91 %), implying the key role of D427 for the acceptor substrate recognition and the stereoselectivity of the enzyme. It is worth noting that this is the first report of DXS mutants that can recognize benzaldehyde as an acceptor substrate and generate both enantiomers of PAC.
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JOURNAL OF ETHNOPHARMACOLOGY
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2024
·
IF 4.8
Mengze Ding,Xiaohan Wei,Changshun Liu,Xiaomei Tan
Ethnopharmacological relevance Allergic rhinitis (AR) is a prevalent nasal inflammatory disorder, and pyroptosis plays a crucial role in aggravating AR. Current medications for AR treatment still have deficiencies, and finding new agents is of great interest. Mahuang Fuzi Xixin decoction (MFXD), an ancient Chinese medicine, is now commonly used to treat AR, which has anti-inflammatory and immunomodulatory effects, but its underlying mechanism is unknown. Aim of this study This study aims to evaluate the effects of MFXD on AR and explore its potential mechanisms in view of the regulatory effect on pyroptosis. Methods MFXD, Mahuang, Fuzi, and Xixin water extracts were analyzed using ultra high performance liquid chromatography-Orbitrap-high-resolution accurate mass spectrometry. In in vivo study, the effects of MFXD on AR treatment were evaluated in an ovalbumin-induced mouse model. Mice were administered saline (control and model groups), MFXD (1.375, 2.75 g/kg), and dexamethasone (2.5 mg/kg) for 13 days. AR symptoms were evaluated by blinded observers. Immunoglobulin E (IgE) and histamine levels were measured using enzyme-linked immunosorbent assays. Expression of pyroptosis-related proteins (NLRP3, ASC, Caspase-1 p10/p20, GSDMD-N and IL-1β) in AR mouse nasal mucosa were estimated by immunohistochemistry. In in vivtro study, the effects of MFXD on pyroptosis were assessed in human nasal epithelial cells (HNEpCs) stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP), and incubated with MFXD (12.5, 25, and 50 μg/mL). Pyroptosis-related protein expression was measured by western blotting. Results Thirty-three compounds in MFXD were identified, including ephedrine, pseudoephedrine, higenamine, aconine, aconitine, benzoylmesaconitine, benzoylhypaconine and hypaconitine. In the in vivo study, oral taken of MFXD/dexamethasone significantly ameliorated AR symptoms, reduced swelling of the nasal mucosa, and decreased the levels of IgE and histamine in AR mice serum. MFXD/dexamethasone attenuated histopathological changes and reduced the expression of pyroptosis-related proteins in nasal mucosa, indicating the inhibitory effect on nasal epithelial pyroptosis. In the in vitro study, MFXD (50 μg/mL) significantly alleviated cytotoxicity, protected cells from swelling and rupture, and downregulated the expression of pyroptosis-related proteins in LPS/ATP-induced HNEpCs. Conclusion MFXD suppressed nasal epithelial pyroptosis by inhibiting the NLRP3/Caspase-1/GSDMD-N signaling pathway, which alleviates AR. Our results offer valuable insights into potential AR therapies and provide evidence for the clinical utilization of MFXD to treat AR.
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ANALYTICAL LETTERS
·
2024
·
IF 1.6
Jiali Ju,Qiaoyu Ding,Jianwei Xie,Guixin Li
A graphene oxide-Ru(bpy)32+-polyaniline-nanocomposite (GO-Ru(bpy)32+-PANI) was prepared to develop a sensitive label-free electrochemiluminescence (ECL) immunosensor for mucoprotein 1 (MUC1). Ru(bpy)32+ and PANI were decorated together on graphene oxide for the first time. The GO-Ru(bpy)32+-PANI material was characterized by scanning electron microscopy (SEM), absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), fluorescence, electrochemical impedance spectroscopy (EIS), and ECL. The GO-Ru(bpy)32+-PANI exhibited excellent stability. The ECL immunosensor for MUC1 was fabricated by covalently immobilizing anti-MUC1 upon GO-Ru(bpy)32+-PANI modified indium-doped tin oxide (ITO) electrode. In the presence of MUC1, a decrease of ECL was observed due to the formation of the anti-MUC1/MUC1 complex. The immunosensor showed a linear relationship from 1 × 10−13 to 1 × 10−7 mg/mL with a detection limit of 8.2 × 10−14 mg/mL. The immunosensor was applied to the determination of MUC1 in human serum.
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IMMUNOLOGY LETTERS
·
2025
·
IF 2.8
Xing Chen,Lixiang Li,Yan Deng,Juan Liao,Hui Meng,Limei Liang,Jie Hu,Dongwei Xie,Guizi Liang
(1) Background Metabolic abnormalities and immune inflammation are key elements within pathogenesis of pulmonary arterial hypertension (PAH). And in PAH patients, aberrant glutamine metabolism has been observed; however, the function of glutaminase 1 (GLS1) in macrophage is still unknown. So we aims to investigate GLS1′s impact upon macrophages in PAH. (2) Methods We firstly constructed an monocrotaline (MCT)-induced PAH rat model. Briefly, the PAH rats were treated with the GLS1 inhibitor BPTES, and various index were evaluated, including hemodynamics, right ventricular function, pulmonary vascular remodeling, macrophage markers, and glutamine metabolism. After that, we polarized bone marrow-derived macrophages (BMDMs) into M1 phenotype and then subjected to BPTES intervention. Finally, we assessed macrophage phenotype, inflammatory markers, and glutamine metabolism indicators, along with the impact of BMDM supernatant on the behavior of pulmonary arterial smooth muscle cells (PASMCs). (3) Results : GLS1 was significantly upregulated in both PAH patients and rats. Treatment with the GLS1 inhibitor BPTES markedly improved pulmonary arterial pressure, right ventricular function, and pulmonary vascular remodeling in PAH rats, while inhibiting M1 macrophage polarization, NLRP3 activation, and the release of pro-inflammatory cytokines. This, in turn, alleviated the proliferation and migration of PASMCs induced by inflammatory stimuli. (4) Conclusion : We propose that targeting GLS1 to reduce M1 macrophage polarization and inflammatory responses may represent a promising therapeutic approach for PAH.
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CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Haihui Liu,Xiaoxia Zhou,Kangli Xu,Heng Zhang,Huan Wang,Hongqing Zhou,Hangrong Chen
Excessive CO 2 emission has caused serious environmental problems, and converting CO 2 to high value-added fuels is attractive for solving energy and environmental crisis. Herein, a novel mesoporous TS-1(mTS-1) zeolite-confined metal oxides nanoclusters Cu-Bi@mTS-1 was developed for efficient photoelectrochemical reduction reaction of CO 2 (PEC CO 2 RR). The catalyst Cu-Bi@mTS-1 as a photocathode showed high activity, achieving a maximum methanol Faraday efficiency (FE CH3OH ) of 93.4 % at −0.7 V vs. RHE. The C 2 product ethanol could be also detected at higher potentials during PEC CO 2 RR. In-situ FTIR results indicate the occurrence of key reaction intermediates *CO, *CHO, *OCCO and *COCHO during the conversion of CO 2 to CH 3 OH and CH 3 CH 2 OH. It is believed that the hierarchically porous structure of mTS-1 is conducive to the enrichment of CO 2 molecules to increase the reactant concentration, also can promote C-C coupling through photoelectric synergism. This work provides a favorable reference for the rational design of photocathodes by confinement effect of porous structure.
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Cell Reports
·
2024
·
IF 7.5
Xueping Li,Jiarui Zhou,Xingmei Liu,Chen Jin,Le Liu,Hongmin Sun,Qian Wang,Qiushi Wang,Ruiying Liu,Xiaoyu Zheng,Yutao Liu,Yu Pang
Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infection (UTI). UPEC invades bladder epithelial cells (BECs) via fusiform vesicles, escapes into the cytosol, and establishes biofilm-like intracellular bacterial communities (IBCs). Nucleoside-diphosphate kinase (NDK) is secreted by pathogenic bacteria to enhance virulence. However, whether NDK is involved in UPEC pathogenesis remains unclear. Here, we find that the lack of ndk impairs the colonization of UPEC CFT073 in mouse bladders and kidneys owing to the impaired ability of UPEC to form IBCs. Furthermore, we demonstrate that NDK inhibits caspase-1-dependent pyroptosis by consuming extracellular ATP, preventing superficial BEC exfoliation, and promoting IBC formation. UPEC utilizes the reactive oxygen species (ROS) sensor OxyR to indirectly activate the regulator integration host factor, which then directly activates ndk expression in response to intracellular ROS. Here, we reveal a signaling transduction pathway that UPEC employs to inhibit superficial BEC exfoliation, thus facilitating acute UTI.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Yi Liu,Shaoyan Wang,Jiarui Liang,Lirong Lu,Yi Xie,Chengrong Qin,Chen Liang,Caoxing Huang,Shuangquan Yao
Demethylation modification of lignin is an effective strategy to overcome the barrier to its high-value conversion. The purpose of this study focuses on the new proton-based ionic liquid (PIL) 1, 2-propanediamine/glycolic acid (PD/GA) as a catalyst and solvent to achieve the targeted oxidation of lignin. The PD/GA solvents have higher selectivity and efficiency. Optimal phenolic hydroxyl (PH)-increment was achieved, demonstrating enhanced demethylating effect on lignin by modulating the acid-base molar ratio, reaction temperature, and reaction time. Compared to ethanolamine/acetic acid (CE/AC) treatment, the PD/GA treatment at molar ratio 1.25, temperature 60 °C, and 3 h increased the PH-content from 37.74 to 59.91 %. Additionally, the lignin treated with PD/GA exhibited excellent recyclability, featuring a larger Brunauer-Emmett-Teller surface area (1.45 m 2 .g −1 ), total pore volume (9.51*10 −3 cm 3 .g −1 ), and mesoporous size (26.15 nm). The treated lignin yielded maximum ultraviolet resistance and antioxidant activity. These results present new avenues for the development of green and efficient lignin demethylation methods.
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ACS Catalysis
·
2018
·
IF 11.384
Tianliang Lu,Junpeng Zou,Yuzhong Zhan,Xiaomei Yang,Yiqiang Wen,Xiangyu Wang,Lipeng Zhou,Jie Xu
Highly efficient oxidation of ethyl lactate (ELA) to ethyl pyruvate (EP) was realized over TS-1 in the presence of aqueous H2O2 (30 wt %) at low temperature without other solvent. A 100% ELA conversion and 97.8% EP yield were obtained at 50 °C after 9 h. The conversion rate of ELA is sensitive to the reaction temperature. High reaction temperature (70 °C) leads to an increase in conversion rate of ELA but causes the fast hydrolysis and decarboxylation of EP to form byproducts of acetic acid and CO2. On the basis of the characterization (pyridine-FTIR and UV–vis) and reaction results, active species of Ti(OOH) were proven. In addition, a nonradical mechanism for conversion of ELA to EP for this catalytic system was proposed. By kinetic analysis, the formation of Ti(OOH) is confirmed as the rate-determining step. The apparent activation energy (103.4 kJ mol–1) was also obtained. Furthermore, TS-1 was highly stable for the oxidation of ethyl lactate. There were almost no change in ELA conversion and EP yield throughout 10 reaction runs.
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RSC Advances
·
2018
·Vol. 8
·期 15
·8372-8384
·
IF 2.936
Guangzheng Zuo,Yuebing Xu,Jiao Zheng,Feng Jiang,Xiaohao Liu
Supported W catalysts were extensively investigated for the conversion of 1-butene and ethylene into propene by metathesis reaction. The performance of catalysts was compared by using unsupported WO3, pure SBA-15, supported W/SBA-15 with different W loadings, varied calcination temperatures, and by changing the pretreatment gas atmosphere. The above catalytic results could be employed to deduce the reaction mechanism combined with characterization techniques such as BET, XRD, UV-vis DRS, Raman, pyridine-IR, XPS, and H2-TPR. In this study, over the investigated W/SBA-15 catalysts, the results showed that the silanol group (Si–OH) in SBA-15 could act as a weak Brønsted acid site for 1-butene isomerization. However, the metathesis reaction was catalyzed by W-carbene species. The initially formed W-carbenes (WCH–CH3) as active sites were derived from the partially reduced isolated tetrahedral WOx species which contained WO or W–OH bonds in W5+ species as corresponding Lewis or Brønsted acid sites. Furthermore, the W/SBA-15 being pretreated by H2O led to a complete loss of the metathesis activity. This was mainly due to the sintering of isolated WOx species to form an inactive crystalline WO3 phase as demonstrated by XRD patterns. On the other hand, the reduction of WOx species remarkably suppressed by H2O pretreatment was also responsible for the metathesis deactivation. This study provides molecular level mechanisms for the several steps involved in the propene production, including 1-butene isomerization, W-carbene formation, and metathesis reaction.
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COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2018
·
IF 4.514
Jiajia Liu,Wei Wang,Richard K.K. Yuen,Zhou Gui,Yuan Hu
SnO 2 nanowires decorated MnO 2 nanosheets hybrids, were prepared and incorporated into epoxy resins to improve the flame retardancy and inhibite the smoke in combustion. SnO 2 -MnO 2 hybrids shows significant improve in flame retardancy, fire toxicity and thermal properties of epoxy nanocomposites, compared to neat epoxy and nanocomposites with a single SnO 2 or MnO 2 . The char residues and glass transition temperature of the epoxy/2 wt% SnO 2 -MnO 2 nanocomposite were remarkably increased. The peak heat release rate of EP/2 wt% SnO 2 -MnO 2 was significantly decreased by 62.9% than that of pure epoxy. TG-FTIR results that the concentration of organic volatiles of epoxy was significantly reduced and the toxic CO was suppressed after incorporating SnO 2 -MnO 2 . The physical barrier for SnO 2 -MnO 2 hybrids and the synergism between the catalysis effect of SnO 2 and MnO 2 can improve the flame retardancy of epoxy resin.
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